The present invention relates to a method for folding sheet-shaped plastic material and to a folded sheet-shaped plastic material obtained by carrying out this method.
The folding of sheets of plastic material, especially for the realization of boxes, packings, etc., which must be available a flat condition and be folded by the user, gives rise to several problems, so that, in most of the cases, the sheets are not made of only one and the same material but are made of several materials, constituting successive layers.
Most of the known folding methods have drawbacks in that the operation must be effected in heated condition, or that the sheet is weakened too much at the place of the folding, if the operation is effected in a cold condition along a weakening line. It is moreover difficult, in this latter case, to determine precisely what will be the resistance to the folding, that is however necessary when the folding is effected with a machine.
The purpose of the present invention is to remove these drawbacks.